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'H. R. GASSEL. PROCESS OF EXTRA-OTING GOLD.

No. 568,427. Patented Sept. 29, 1896.

W m m THE nonms PETERS cu. Pno'rau'mo UN TED STATES ATENT men HENRY R. CASSEL, on NEW YORK, N'QY.

PROCESS OF EXTRACTING GOLD.

SPECIFICATION forming part of Letters Patent No. 568,427, dated September 29, 1896.

Application filed November 15,1895.

To all whom it may concern.-

Be it known that I, HENRY R. CASSEL, of New York city, New York, have invented an Improved Process of Extracting Gold, of which the following is a specification.

This invention relates to an improved process in the art of extracting gold from ores or auriferous materials by the use of bromin and the subsequent recovery of the bromin.

It is well known that an aqueous solution of bromin dissolves gold very rapidly, but in the extraction of gold from ores it is necessary to use a greater quantity of bromin than the gold would require for its solution, first, because of the presence of other metals which also combine with the bromin, and, secondly, because the use of a greater quantity of bromin than is necessary to combine with both the precious and base metals insures a rapid and complete extraction of the gold. Inasmuch, however, as bromin is expensive, its use can only be rendered commercially available when means for the recovery of the excess used are provided.

I propose to recover the bromin in a simple, practical, and inexpensive manner, after it has acted upon the gold, by mixing it with a solvent which does not precipitate the gold and then separating it from such solvent.

In the accompanying drawings, Figure 1 is an elevation, partly in section, of an apparatus for carrying my invention into effect; and Fig. 2is a cross-section on line 2 2, Fig. 1.

The pulverized auriferous ore is treated in a revolving barrel a with an aqueous solution of bromin. The quantity of bromin employed for each ton of ore depends entirely upon the character of the ore, about five to fifteen pounds being generally sufficient, though more may, if necessary, be used. By rotating the barrel for about two hours the bromin will combine with the gold, and the latter will be converted into a bromid in solution. This solution is now filtered and conducted into a second barrel, tank, or vessol b, containing suitable blades or stirrers 0. Into this barrel I introduce a solvent for the free bromin which is not miscible with the, water and does not precipitate the gold. The solvents I propose to use preferably are the hydrocarbons, bisulphid of carbon, carbon tetrachlorid, and neutral oils, which for Serial N0.569,01l. (N0 specimens.)

the purpose of this invention are equivalents. The quantity of solvent employed depends upon the quantity of bromin used, an excess of the solvent being desirable. The solvent being introduced into the barrelb, as de* scribed, the latter is revolved for from about fifteen to thirty minutes, when the bromin will all have been absorbed by the solvent. The rotation of the barrel being stopped, the mixture is allowed to stand, when the solvent containing the bromin will separate from the gold solution by specific gravity. The gold solution is now withdrawn from the barrel 1) into a suitable tank d, in which the gold is precipitated in any suitable or well-known manner.

In order to separate the bromin from the solvent, I prefer to add thereto a suitable alkali, such as potash or soda, &c., which will combine with the bromin and form bromid and bromate salts in solution, which are withdrawn by tap e. The solvent is thus left over in the barrel and can be used' again. The bromid salts removed by tap e are treated in any of the well-known manners, as by the addition of an acid, to set the bromin free.

If soda is used as the alkali which is to combine wit-h the bromin, I use about one part per weight of sodium hydrate for each part of bromin by weight to be recovered.

It will be seen that by this process the bromin as well as the solvent is recovered, so that the process is economical and commercially practicable.

What I claim is- 1. The process of extracting gold from ores, which consists in treating the ores with an aqueous bromin solution in excess, then adding a solvent for the free bromin, withdrawin g the dissolved gold, and separating the bromin from the solvent, substantially as specified.

2. The process of extracting gold from ores, which consists in treating the ores with an aqueous bromin solution in excess, then adding a hydrocarbon,withdrawing the dissolved gold, and separating the free bromin from the hydrocarbon, substantially as specified.

3. The process of extracting gold from ores, which consists in treating the ores with an aqueous bromid solution in excess, then addin g a solvent for the free bromin, withdrawing the dissolved gold, and adding an alkali gold and adding an alkali to the bromin so to the bromin solution, to separate the brolution, to separate the free bromin from the IO min from the solvent, substantially as speoihydrocarbon, substantially as specified.

4:. The process of extracting gold from ores, HENRY R. GASSEL. which consists in treating the ores with an "Witnesses: aqueous bromin solution in excess, then add- F. V. BRIESEN,

in g a hydrocarbon Withdrawing the dissolved FREDERICK SEIBEL. 

